A method for treating antibiotic wastewater using a visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode

Abstract

The present invention discloses a method for treating antibiotic wastewater using a visible light-responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode. The method uses the visible light-responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode as an anode to treat the antibiotics in the wastewater through a photoelectrocatalytic reaction. The visible light-responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode is formed using a titanium dioxide electrode sheet as an electrode substrate through electrochemical reduction autodoping, pulse deposition, metal-organic framework (MOF) self-assembly, and engraving reduction processes. The method solves the problem of hindered mass transfer rate between MOFs and the substrate and improves the dispersion of MOFs in the substrate, thereby exhibiting advantages such as good catalytic effect and strong light utilization capacity. Furthermore, it has the advantages of rapid recycling, strong practicality, and no secondary pollution. This method is a widely adopted treatment method for effectively removing antibiotics from water bodies and has high use value and application prospects.

Description

Technical Field

[0001] The invention belongs to the technical field of photocatalytic electrode material preparation, and particularly relates to a method for treating antibiotic wastewater by utilizing a visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode. Background Art

[0002] Recently, there is an urgent need to utilize MOFs in non-powdered forms for various chemical reactions. These strategies, such as aerogels for adsorption and biochar-supported persulfate activation, effectively avoid the challenges of traditional powdered catalyst separation and recovery. However, they also introduce a variety of unknown matrices, and effective synthetic techniques for precisely controlling the dispersion of MOFs within them remain elusive. Furthermore, addressing the drawback of MOFs' easy recombination of electrons and holes in photocatalysis, effective separation of photogenerated electrons and holes and simultaneous removal of recalcitrant organic chemical pollutants are essential. Expanding MOFs' participation in the oxidation of recalcitrant organic compounds as photoelectrodes appears feasible. This approach utilizes electrochemically assisted photocatalysis, generating a potential gradient within the photoelectrode by applying a specific anodic bias, forcing photogenerated electrons toward the counter electrode for efficient electron-hole separation. However, current research on the application of MOFs for photoelectrocatalytic degradation of organic pollutants is extremely limited, and most studies have employed MOF powders coated on conductive glass to form bulk electrodes, which reduces the mass transfer rate between the guest MOFs and the substrate FTO. In order to solve the above-mentioned problems about the unknown nature of the matrix, the dispersion of MOFs in the matrix, and the reduced mass transfer rate between MOFs and the matrix, it is necessary to find a matrix with a certain research basis and a unique structure to load MOFs and expand the application of MOFs in photoelectrocatalysis through an effective composite method.

[0003] Titanium dioxide (TiO2), a semiconducting metal oxide, has amassed a substantial research base over the past decade. TiO2 nanotubes, known for their corrosion resistance, large surface area, ease of synthesis, and tunable morphology, have been considered as substrates for MOFs loading for photoelectrocatalytic applications due to their geometric, electrical, and optical properties. TiO2 nanotubes prepared by conventional alkaline hydrothermal methods are typically disordered and small in diameter, making it difficult for electroactive materials to enter the nanotubes, resulting in unutilized inner surfaces. Electrochemical anodization methods, however, allow for precise control of nanotube structural parameters (such as pore size, wall thickness, and length) by adjusting oxidation conditions. This provides more accessible space for reactions and facilitates the full utilization of electroactive materials. Furthermore, the ordered and tightly packed nanotubes provide a robust support structure for the desired loading of electroactive materials while minimizing light reflection losses, preventing photons entering the nanotubes from escaping due to multiple scattering from the nanotube walls. Well-aligned TiO2 nanotubes prepared by electrochemical anodization have been shown to be promising photoanodes for applications in water purification, hydrogen production, antibacterial treatment, and photovoltaic cell power generation.

[0004] However, TiO2 nanotubes are not an ideal photoelectrode matrix, mainly due to their large band gap limitations, which leads to low efficiency when irradiated with visible light. An effective way to overcome this obstacle is to use non-metallic doping, transition metal sensitization, or coupling with narrow band gap semiconductors to directly inject photogenerated electrons into the conduction band of TiO2. MOFs contain both transition metal centers and semiconductor-like properties, so it is possible to consider combining the two. In addition, the low dispersion of MOFs on nanotubes and the weak bond contact between MOFs and semiconductors also limit the visible light response and charge separation of the photoelectrode. Therefore, it is necessary to choose a more effective method to improve the dispersion and compactness of MOFs on TiO2 nanotubes in order to obtain a photoelectrode with high catalytic activity for photoelectrocatalytic removal of antibiotics in water. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the existing technology and provide a method for treating antibiotic wastewater using visible light responsive semiconductor-MOFs hybrid photoelectrocatalytic material electrodes with fast recycling, good removal effect, high circulation efficiency and strong practicality.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A method for treating antibiotic wastewater using a visible light-responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode. The method uses the visible light-responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode as an anode to treat antibiotics in the wastewater through a photoelectrocatalytic reaction. The visible light-responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode is a titanium dioxide electrode sheet with oxygen-deficient titanium dioxide nanotubes as an electrode substrate. The oxygen-deficient titanium dioxide nanotubes are loaded with a derivative of MOFs. The MOFs derivative is Ar-Fe2O3.

[0008] The above method is further improved, wherein the oxygen-deficient titanium dioxide nanotubes have oxygen vacancies; the oxygen-deficient titanium dioxide nanotubes realize Ti 3+ of self-doping.

[0009] The above method is further improved, wherein the preparation method of the visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode comprises the following steps:

[0010] S1, immersing titanium foil in an electrolyte containing sodium fluoride and sodium sulfate, and performing anodization with graphite as a counter electrode to obtain amorphous TiO2;

[0011] S2, calcining the amorphous TiO2 obtained in step S1 to obtain a titanium dioxide electrode sheet;

[0012] S3. The titanium dioxide electrode sheet obtained in step S2 is used as a working electrode, the platinum electrode is used as a counter electrode, and Ag / AgCl is used as a reference electrode. The electrodes are reduced in sodium sulfate solution and ammonium sulfate solution in sequence, and then electrodeposited in ferrous sulfate solution to obtain Fe-doped oxygen-deficient titanium dioxide nanotubes.

[0013] S4. The titanium dioxide electrode sheet obtained in step S3 is mixed with N-N-dimethylformamide, 1,3,5-trimethylbenzenecarboxylic acid, nitric acid, and hydrofluoric acid for in-situ growth to obtain a visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode.

[0014] 4. The above method is further improved, wherein in step S1, the titanium foil is ultrasonically treated in acetone and ethanol for 15 to 20 minutes each before use, then ultrasonically treated in a chemical polishing solution of HF:HNO3:H2O=1:3:6 for 30 seconds, then allowed to stand for 30 seconds, and finally ultrasonically treated in ultrapure water for 15 minutes; the concentration of sodium fluoride in the electrolyte containing sodium fluoride and sodium sulfate is 0.3wt% to 0.5wt%, and the concentration of sodium sulfate is 0.5mol / L to 1mol / L; the DC voltage of the control power supply during the anodization process is 20V; and the anodization time is 3 to 5 hours;

[0015] The above method is further improved, in step S2, the heating rate during the calcination process is 5°C / min to 7°C / min; the calcination temperature is 400°C to 500°C; and the calcination time is 1h to 2h.

[0016] The above method is further improved, and the specific steps of step S3 are:

[0017] (1) Using a titanium dioxide electrode as the anode, a platinum electrode as the counter electrode, and Ag / AgCl as the reference electrode, the reduction reaction was carried out in a 0.1 mol / L sodium sulfate solution at an applied voltage of -1.3 V for 10 to 20 minutes.

[0018] (2) The titanium dioxide electrode in step (1) is used as the anode, the platinum electrode is used as the counter electrode, and Ag / AgCl is used as the reference electrode, and reduced in a 1 mol / L ammonium sulfate solution at an applied voltage of -1.5 V for 3s to 5s;

[0019] (3) The titanium dioxide electrode sheet in step (2) is used as the anode, the platinum electrode is used as the counter electrode, and Ag / AgCl is used as the reference electrode, and is deposited in a 300 g / L ferrous sulfate solution for 3 min to 10 min.

[0020] The above method is further improved, and the specific steps of step S4 are:

[0021] (1) Immerse the titanium dioxide electrode sheet in a mixed solution of N-N-dimethylformamide, 1,3,5-trimethylbenzene carboxylic acid, nitric acid, and hydrofluoric acid and maintain it at 150°C for 20 to 24 hours;

[0022] (2) The titanium dioxide electrode sheet in step (1) is taken out, washed, and dried to obtain a visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode.

[0023] The above method is further improved, wherein in step (1), the mixed solution of N-dimethylformamide, 1,3,5-pyromellitic acid, nitric acid, and hydrofluoric acid comprises 30 mL to 50 mL of N-dimethylformamide, 1.0 g to 1.5 g of 1,3,5-pyromellitic acid, 0.27 mL to 0.30 mL of nitric acid, and 0.35 mL to 0.40 mL of hydrofluoric acid. In step (2), the washing is performed with ethanol and ultrapure water; the drying is performed in an oven; the drying temperature is 60° C. to 80° C., and the drying time is 15 min to 20 min.

[0024] The above method is further improved, and the method includes the following steps: using a visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode as an anode, a platinum sheet as a counter electrode, and an Ag / AgCl electrode as a reference electrode, placing them in antibiotic wastewater containing an electrolyte to carry out a photoelectrocatalytic reaction to complete the treatment of the antibiotic wastewater.

[0025] The above method is further improved in that the photoelectrocatalytic reaction is carried out under light conditions, the voltage during the photoelectrocatalytic reaction is 1V to 3V, and the time of the photoelectrocatalytic reaction is 1.5h.

[0026] The above method is further improved, wherein the antibiotic in the antibiotic wastewater containing electrolytes is tetracycline; the concentration of the antibiotic in the antibiotic wastewater containing electrolytes is 20 mg / L; the concentration of the electrolyte in the antibiotic wastewater containing electrolytes is 25 mmol / L to 100 mmol / L; the electrolyte in the antibiotic wastewater containing electrolytes is sodium sulfate; and the pH value of the antibiotic wastewater containing electrolytes is 5.0 to 5.8.

[0027] Compared with the prior art, the advantages of the present invention are:

[0028] (1) The present invention provides a method for treating antibiotic wastewater using a visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode, wherein the visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode is used as an anode, a platinum sheet is used as a counter electrode, and an Ag / AgCl electrode is used as a reference electrode. The electrodes are placed in antibiotic wastewater containing an electrolyte to carry out a photoelectrocatalytic reaction, thereby achieving catalytic degradation of the antibiotics in the wastewater. Taking tetracycline wastewater as an example, compared with unmodified TiO2, the reaction rate and degradation efficiency of the visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode were increased by 29.8 times and 3.23 times, respectively. The photoelectrocatalytic synergy factor can reach 4.20, and the electrode has excellent degradation ability for a variety of antibiotics and real samples. After 8 cycles, the degradation rate of tetracycline wastewater by the visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode decreased by only 1.7%. It solves the problem of obstructed mass transfer rate between MOFs and the substrate, and improves the dispersion of MOFs in the substrate, thereby showing good catalytic effect and strong light utilization ability. It also has the advantages of fast recycling, strong practicality, and no secondary pollution. It is a treatment method that can be widely adopted and can effectively remove antibiotics in water bodies. It has high use value and application prospects.

[0029] (2) The visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode used in the present invention has oxygen-deficient titanium dioxide nanotubes as the electrode substrate; the electrode substrate is loaded with a derivative of MIL-100 (Fe) - Ar-Fe2O3. In the present invention, Ti is prepared by electrochemical reduction.3+ Self-doped TiO2-NTs not only achieve photosensitization of nanotubes, but also improve the conductivity of the bottom of the nanotube pores. Further, the resistance difference between the bottom and top of the nanotubes is used to deposit Fe metal centers with abundant availability, low cost and non-toxic properties into the nanotubes through pulse deposition. After self-assembly to form MIL-100(Fe), Ar-Fe2O3 / Ti with good photoelectrocatalytic activity is obtained by calcination under argon. 3+ -TiO2-NTs photoelectrode. The vertical orientation of the nanotubes provides a good electron path for charge transfer over a large internal surface area. The pulse deposition of the metal center Fe improves its dispersion, which is beneficial to the subsequent self-assembly of MIL-100(Fe) to improve the interfacial mass transfer rate and compactness. The Ar-Fe2O3 after the engraving reduction process retains the large specific surface area and porous structure of MIL-100(Fe) to improve interfacial adsorption, and its interaction with Ti 3+ The heterojunction formed by TiO2-NTs can significantly improve interfacial charge transfer. Compared with existing technologies, the present invention's visible-light-responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode has advantages such as good conductivity, strong mechanical stability, excellent catalytic performance, and strong light utilization capabilities. It solves the problem of low efficiency under visible light irradiation caused by the large band gap of semiconductor TiO2, improves the dispersion of MOFs in the matrix and the mass transfer rate between MOFs and the matrix, and significantly enhances conductivity, photoelectrocatalytic activity, and compactness, enabling efficient degradation of antibiotics under visible light. Furthermore, the electrode is easily recyclable, possessing high promotion value and promising application prospects.

[0030] (3) In the present invention, for the first time, a visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode with good catalytic effect, strong light utilization ability and good cycle stability is synthesized by combining electrochemical deposition and in situ self-assembly. The electrode has the characteristics of strong tightness between the conductive substrate and the photosensitizer, uniform dispersion of the photosensitizer, convenient recovery, wide application, easy operation and strong practicality. It is suitable for large-scale preparation and is conducive to industrial application.

[0031] (4) In the present invention, amorphous TiO2 having a hollow nanotube structure is prepared by an anodic oxidation method, and the bottom of the tube is converted into a highly conductive state by electrochemical reduction while the tube wall is kept in a low conductive state. The resistance difference between the bottom and top of the nanotube is further utilized to deposit Fe metal centers with abundant availability, low cost and non-toxic properties into the nanotube by pulse deposition. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0033] Figure 1The visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode (Ar-Fe2O3 / Ti 3+ -TiO2-NTs), oxygen-deficient TiO2 nanotube photoelectrode (Ti 3+ -TiO2-NTs), TiO2-NTs with Fe deposited in Comparative Example 3 3+ -TiO2-NTs nanotube photoelectrode (Fe-Ti 3+ -TiO2-NTs), MIL-100(Fe) self-assembled Ti prepared in Comparative Example 4 3+ -TiO2-NTs nanotube photoelectrode (MIL-100(Fe) / Ti 3+ -TiO2-NTs), where (a) is Ti 3+ -TiO2-NTs, (b) Fe-Ti 3+ -TiO2-NTs, (c) is MIL-100(Fe) / Ti 3+ -TiO2-NTs, (d), (e) and (f) are Ar-Fe2O3 / Ti 3+ -TiO2-NTs.

[0034] Figure 2 The visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode (Ar-Fe2O3 / Ti 3+ -TiO2-NTs), pure TiO2 nanotube photoelectrode (TiO2-NTs) prepared in Comparative Example 1, oxygen-deficient TiO2 nanotube photoelectrode (TiO2-NTs) prepared in Comparative Example 2 3+ -TiO2-NTs), TiO2-NTs with Fe deposited in Comparative Example 3 3+ -TiO2-NTs nanotube photoelectrode (Fe-Ti 3+ -TiO2-NTs), MIL-100(Fe) self-assembled Ti prepared in Comparative Example 4 3+ -TiO2-NTs nanotube photoelectrode (MIL-100(Fe) / Ti 3+ -TiO2-NTs) X-ray diffraction pattern.

[0035] Figure 3 The visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode (Ar-Fe2O3 / Ti 3+ -TiO2-NTs) the pure TiO2 nanotube electrode (TiO2-NTs) prepared in Comparative Example 1, the oxygen-deficient TiO2 nanotube electrode (TiO2-NTs) prepared in Comparative Example 2 3+ -TiO2-NTs), TiO2-NTs with Fe deposited in Comparative Example 33+ -TiO2-NTs nanotube photoelectrode (Fe-Ti 3+ -TiO2-NTs), MIL-100(Fe) self-assembled Ti prepared in Comparative Example 4 3+ -TiO2-NTs nanotube photoelectrode (MIL-100(Fe) / Ti 3+ -TiO2-NTs) X-ray photoelectron spectrum.

[0036] Figure 4 The visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode (Ar-Fe2O3 / Ti 3+ -TiO2-NTs) the pure TiO2 nanotube electrode (TiO2-NTs) prepared in Comparative Example 1, the oxygen-deficient TiO2 nanotube electrode (TiO2-NTs) prepared in Comparative Example 2 3+ -TiO2-NTs), TiO2-NTs with Fe deposited in Comparative Example 3 3+ -TiO2-NTs nanotube photoelectrode (Fe-Ti 3+ -TiO2-NTs), MIL-100(Fe) self-assembled Ti prepared in Comparative Example 4 3+ -TiO2-NTs nanotube photoelectrode (MIL-100(Fe) / Ti 3+ -TiO2-NTs) by UV-visible diffuse reflectance spectra.

[0037] Figure 5 The visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode (Ar-Fe2O3 / Ti 3+ -TiO2-NTs), the catalytic degradation effect diagram of the pure TiO2 nanotube electrode (TiO2-NTs) prepared in comparative example 1 and the corresponding reaction rate diagram, where (a) is the degradation effect and (b) is the reaction rate.

[0038] Figure 6 The visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode (Ar-Fe2O3 / Ti 3+ -TiO2-NTs) on tetracycline degradation effect under different conditions and the corresponding reaction rate diagram, where (a) is the degradation effect and (b) is the reaction rate.

[0039] Figure 7 The visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode (Ar-Fe2O3 / Ti 3+ -TiO2-NTs) on tetracycline degradation effect and reaction rate diagram at different voltages, where (a) is the degradation effect and (b) is the reaction rate.

[0040] Figure 8 The visible light responsive semiconductor-MOFs hybrid photoelectrocatalytic material electrode (Ar-Fe2O3 / Ti 3+ -TiO2-NTs) on tetracycline degradation effect and reaction rate diagram at different pH, where (a) is the degradation effect and (b) is the reaction rate.

[0041] Figure 9 The visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode (Ar-Fe2O3 / Ti 3+ -TiO2-NTs) on the degradation effect of tetracycline under different electrochemical deposition times and different light intensities. DETAILED DESCRIPTION

[0042] The present invention will be further described below in conjunction with the accompanying drawings and specific preferred embodiments, but the scope of protection of the present invention is not limited thereby.

[0043] The raw materials and instruments used in the following examples are all commercially available. In the following examples, unless otherwise specified, the data obtained are the average values ​​of more than three repeated experiments.

[0044] Example 1

[0045] A method for treating antibiotic wastewater using a visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode, specifically treating tetracycline in the wastewater through a photoelectrocatalytic reaction using the visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode as an anode, comprising the following steps:

[0046] Material electrodes (TiO2-NTs, Ti 3+ -TiO2-NTs, Fe-Ti 3+ -TiO2-NTs, MIL-100(Fe) / Ti 3+ -TiO2-NTs, Ar-Fe2O3 / Ti 3+ -TiO2-NTs) as the anode, a platinum electrode as the counter electrode, and an Ag / AgCl electrode as the reference electrode were placed in 60 mL of tetracycline wastewater containing sodium sulfate (the concentration of sodium sulfate in the wastewater was 25 mmol / L, the concentration of tetracycline was 20 mg / L, and the pH was 5.3) for a photoelectrocatalytic reaction for 90 minutes. The photoelectrocatalytic reaction was carried out under a visible light source at a voltage of 2.0 V to complete the treatment of tetracycline.

[0047] In this embodiment, the visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode (Ar-Fe2O3 / Ti 3+-TiO2-NTs), with oxygen-deficient titanium dioxide electrode sheets as electrode substrates, and the MOFs derivatives loaded on the electrode sheets are Ar-Fe2O3. Oxygen-deficient titanium dioxide nanotubes have oxygen vacancies, and oxygen-deficient titanium dioxide nanotubes realize Ti 3+ of self-doping.

[0048] A visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode (Ar-Fe2O3 / Ti 3+ -TiO2-NTs) preparation method, comprising the following steps:

[0049] (1) 3.5×3.5cm 2 Titanium foil (sheet) was ultrasonically treated in acetone and ethanol, respectively, for 15 minutes each, then immersed in a chemical polishing solution of HF:HNO3:H2O = 1:3:6 for ultrasonic treatment for 30 seconds, allowed to stand for 30 seconds, and then ultrasonically treated in ultrapure water for 15 minutes; after treatment, the titanium foil was immersed in 130 mL of an electrolyte containing sodium fluoride and sodium sulfate (the concentration of sodium fluoride in the electrolyte was 0.5 wt% and the concentration of sodium sulfate was 0.5 mol / L), anodized for 5 hours using graphite as a counter electrode and a constant DC power supply voltage of 20 V to obtain amorphous TiO2.

[0050] (2) The amorphous TiO2 in step (1) is placed in a crucible, heated to 450°C at a heating rate of 5°C / min, and calcined for 2 hours to obtain an electrode substrate mainly having an anatase phase structure, namely a titanium dioxide electrode sheet, named TiO2-NTs.

[0051] (3) The titanium dioxide electrode sheet in step (2) was used as the anode, the platinum electrode was used as the counter electrode, and Ag / AgCl was used as the reference electrode. The electrode substrate with oxygen vacancies was obtained at an applied voltage of -1.3 V in a 0.1 mol / L sodium sulfate solution, which was named TiO2 electrode sheet. 3+ -TiO2-NTs.

[0052] (4) The oxygen-deficient titanium dioxide electrode sheet in step (3) was used as the anode, the platinum electrode was used as the counter electrode, and Ag / AgCl was used as the reference electrode. The electrode was reduced in a 1 mol / L ammonium sulfate solution at an applied voltage of -1.5 V for 3 s and deposited in a 300 g / L ferrous sulfate solution for 5 min to obtain an electrode substrate with Fe deposited on the bottom and wall of the nanotubes, namely, an Fe-doped oxygen-deficient titanium dioxide electrode sheet, named Fe-Ti 3+ -TiO2-NTs.

[0053] (5) 1,3,5-trimethylbenzene tricarboxylic acid was ultrasonically dissolved in N-N-dimethylformamide, 0.27 mL HNO3 and 0.35 mL HF were added, and the mixture was thoroughly mixed to obtain a mixed solution; the Fe-doped oxygen-deficient titanium dioxide electrode sheet in step (4) was immersed in a mixed solution of N-N-dimethylformamide, 1,3,5-trimethylbenzene tricarboxylic acid, nitric acid, and hydrofluoric acid, and maintained at 150°C for 24 h. After the hydrothermal self-assembly was completed, the obtained material was taken out and washed with ethanol and ultrapure water. The washed material was dried in an oven at 60°C for 15 min to 20 min to obtain MIL-100(Fe) / Ti 3+ -TiO2-NTs.

[0054] (6) The electrode sheet obtained in step (5) was heated to 450°C at a heating rate of 5°C / min under argon and calcined for 2h to complete the engraving reduction process, thereby obtaining a visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode, named Ar-Fe2O3 / Ti 3+ -TiO2-NTs.

[0055] In this embodiment, the preparation method of pure TiO2 nanotube electrode (TiO2-NTs) is different from that of visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode (Ar-Fe2O3 / Ti 3+ The preparation method of pure TiO2 nanotube electrode (TiO2-NTs) is the same as that of pure TiO2 nanotube electrode (TiO2-NTs), except that the preparation method includes the following steps:

[0056] 1) 3.5×3.5cm 2 Titanium foil (sheet) was ultrasonically treated in acetone and ethanol, respectively, for 15 minutes each, then immersed in a chemical polishing solution of HF:HNO:H2O = 1:3:6 for ultrasonic treatment for 30 seconds, allowed to stand for 30 seconds, and then ultrasonically treated in ultrapure water for 15 minutes; after treatment, the titanium foil was immersed in 130 mL of an electrolyte containing sodium fluoride and sodium sulfate (the concentration of sodium fluoride in the electrolyte was 0.5 wt% and the concentration of sodium sulfate was 0.5 mol / L), anodized for 5 hours using graphite as a counter electrode and a constant DC power supply voltage of 20 V to obtain amorphous TiO2.

[0057] 2) The amorphous TiO2 prepared in step 1) was placed in a crucible, heated to 450°C at a heating rate of 5°C / min and calcined for 2 h to obtain a pure TiO2 nanotube electrode, which was designated as TiO2-NTs.

[0058] In this embodiment, the Ti 3+ -TiO2-NTs preparation method, and visible light response semiconductor heterojunction hybrid photoelectrocatalytic material electrode (Ar-Fe2O3 / Ti 3+-TiO2-NTs) are prepared in the same way, except that: 3+ The preparation of TiO2-NTs does not include the processes of electrodeposition, hydrothermal self-assembly, and argon engraving reduction, but includes an electrochemical reduction process, including the following steps:

[0059] 1) 3.5×3.5cm 2 Titanium foil (sheet) was ultrasonically treated in acetone and ethanol, respectively, for 15 minutes each, then immersed in a chemical polishing solution of HF:HNO3:H2O = 1:3:6 for ultrasonic treatment for 30 seconds, allowed to stand for 30 seconds, and then ultrasonically treated in ultrapure water for 15 minutes; after treatment, the titanium foil was immersed in 130 mL of an electrolyte containing sodium fluoride and sodium sulfate (the concentration of sodium fluoride in the electrolyte was 0.5 wt% and the concentration of sodium sulfate was 0.5 mol / L), anodized for 5 hours using graphite as a counter electrode and a constant DC power supply voltage of 20 V to obtain amorphous TiO2.

[0060] 2) The amorphous TiO2 prepared in step 1) is placed in a crucible, heated to 450°C at a heating rate of 5°C / min, and calcined for 2 hours to obtain an electrode substrate having an anatase phase structure, i.e., a titanium dioxide electrode sheet.

[0061] 3) The titanium dioxide electrode sheet in step 2) was used as the anode, the platinum electrode was used as the counter electrode, and the Ag / AgCl was used as the reference electrode. The electrode substrate with oxygen vacancies was obtained at an applied voltage of -1.3 V in a 0.1 mol / L sodium sulfate solution, which was marked as an oxygen-deficient titanium dioxide electrode sheet. 3+ -TiO2-NTs.

[0062] In this embodiment, the Fe-Ti 3+ -TiO2-NTs preparation method, and visible light response semiconductor heterojunction hybrid photoelectrocatalytic material electrode (Ar-Fe2O3 / Ti 3+ -TiO2-NTs) are prepared in the same way, except that: Fe-Ti 3+ The preparation of TiO2-NTs does not include hydrothermal self-assembly and argon engraving reduction processes, but includes electrochemical reduction and electrodeposition processes, including the following steps:

[0063] 1) 3.5×3.5cm 2Titanium foil (sheet) was ultrasonically treated in acetone and ethanol, respectively, for 15 minutes each, then immersed in a chemical polishing solution of HF:HNO3:H2O = 1:3:6 for ultrasonic treatment for 30 seconds, allowed to stand for 30 seconds, and then ultrasonically treated in ultrapure water for 15 minutes; after treatment, the titanium foil was immersed in 130 mL of an electrolyte containing sodium fluoride and sodium sulfate (the concentration of sodium fluoride in the electrolyte was 0.5 wt% and the concentration of sodium sulfate was 0.5 mol / L), anodized for 5 hours using graphite as a counter electrode and a constant DC power supply voltage of 20 V to obtain amorphous TiO2.

[0064] 2) The amorphous TiO2 prepared in step 1) is placed in a crucible, heated to 450°C at a heating rate of 5°C / min, and calcined for 2 hours to obtain an electrode substrate having an anatase phase structure, i.e., a titanium dioxide electrode sheet.

[0065] 3) The titanium dioxide electrode sheet in step 2) is used as the anode, the platinum electrode is used as the counter electrode, and Ag / AgCl is used as the reference electrode. The reduction is carried out in a 0.1 mol / L sodium sulfate solution at an applied voltage of -1.3 V for 20 min to obtain an electrode substrate with oxygen vacancies, i.e., an oxygen-deficient titanium dioxide electrode sheet.

[0066] 4) The titanium dioxide electrode sheet in step 3) was used as the anode, the platinum electrode was used as the counter electrode, and the Ag / AgCl was used as the reference electrode. The titanium dioxide electrode sheet was reduced in a 1 mol / L ammonium sulfate solution at an applied voltage of -1.5 V for 3 s and deposited in a 300 g / L ferrous sulfate solution for 5 min. The obtained material was taken out and washed with ultrapure water. The washed material was dried in an oven at 60°C for 15 min to 20 min to obtain an electrode substrate with Fe deposited on the bottom and wall of the nanotubes, which was an Fe-doped oxygen-deficient titanium dioxide electrode sheet, denoted as Fe-Ti 3+ -TiO2-NTs.

[0067] In this embodiment, the MIL-100(Fe) / Ti 3+ -TiO2-NTs preparation method, and visible light response semiconductor heterojunction hybrid photoelectrocatalytic material electrode (Ar-Fe2O3 / Ti 3+ -TiO2-NTs) are prepared in the same way, with the only difference being that: MIL-100(Fe) / Ti 3+ The preparation of TiO2-NTs does not involve argon sintering, but involves electrochemical reduction, electrodeposition, and hydrothermal self-assembly, including the following steps:

[0068] 1) 3.5×3.5cm 2Titanium foil (sheet) was ultrasonically treated in acetone and ethanol, respectively, for 15 minutes each, then immersed in a chemical polishing solution of HF:HNO3:H2O = 1:3:6 for ultrasonic treatment for 30 seconds, allowed to stand for 30 seconds, and then ultrasonically treated in ultrapure water for 15 minutes; after treatment, the titanium foil was immersed in 130 mL of an electrolyte containing sodium fluoride and sodium sulfate (the concentration of sodium fluoride in the electrolyte was 0.5 wt% and the concentration of sodium sulfate was 0.5 mol / L), anodized for 5 hours using graphite as a counter electrode and a constant DC power supply voltage of 20 V to obtain amorphous TiO2.

[0069] 2) The amorphous TiO2 prepared in step 1) is placed in a crucible, heated to 450°C at a heating rate of 5°C / min, and calcined for 2 hours to obtain an electrode substrate having an anatase phase structure, i.e., a titanium dioxide electrode sheet.

[0070] 3) The titanium dioxide electrode sheet in step 2) is used as the anode, the platinum electrode is used as the counter electrode, and the Ag / AgCl is used as the reference electrode. The reduction is carried out in a 0.1 mol / l sodium sulfate solution at an applied voltage of -1.3 V for 20 min to obtain an electrode substrate with oxygen vacancies, i.e., an oxygen-deficient titanium dioxide electrode sheet.

[0071] 4) The titanium dioxide electrode sheet in step 3) is used as the anode, the platinum electrode is used as the counter electrode, and Ag / AgCl is used as the reference electrode. The electrode is reduced in a 1 mol / L ammonium sulfate solution at an applied voltage of -1.5 V for 3 s and deposited in a 300 g / L ferrous sulfate solution for 5 min to obtain an electrode substrate with Fe deposited on the bottom and wall of the nanotubes, i.e., an Fe-doped oxygen-deficient titanium dioxide electrode sheet.

[0072] 5) ultrasonically dissolving 1,3,5-trimethylbenzene tricarboxylic acid in NN dimethylformamide, adding 0.27 mL HNO3 and 0.35 mL HF, and mixing thoroughly to obtain a mixed solution; immersing the titanium dioxide electrode sheet in step 4) in a mixed solution of NN dimethylformamide, 1,3,5-trimethylbenzene tricarboxylic acid, nitric acid, and hydrofluoric acid, maintaining 150 ° C for 24 hours, taking out, and washing the obtained material with ethanol and ultrapure water. The washed material is dried in an oven at 60 ° C for 15 min to 20 min to obtain a visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode, named MIL-100 (Fe) / Ti 3+ -TiO2-NTs.

[0073] Figure 1 The visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode (Ar-Fe2O3 / Ti 3+ -TiO2-NTs), oxygen-deficient TiO2 nanotube photoelectrode (TiO2-NTs) in Comparative Example 2 3+-TiO2-NTs), TiO2-NTs with Fe deposited in Comparative Example 3 3+ -TiO2-NTs nanotube photoelectrode (Fe-Ti 3+ -TiO2-NTs), MIL-100(Fe) self-assembled Ti prepared in Comparative Example 4 3+ -TiO2-NTs nanotube photoelectrode (MIL-100(Fe) / Ti 3+ -TiO2-NTs), where (a) is Ti 3+ -TiO2-NTs, (b) Fe-Ti 3+ -TiO2-NTs, (c) is MIL-100(Fe) / Ti 3+ -TiO2-NTs, (d), (e) and (f) are Ar-Fe2O3 / Ti 3+ -TiO2-NTs. Figure 1 a As can be seen, a vertically grown nanotube array was successfully prepared on the titanium foil surface. 3+ -TiO2-NTs array electrodes exhibit a highly ordered structure and vertically oriented hollow tubes. After electrochemical deposition of Fe, Ti 3+ -TiO2-NTs matrix is ​​uniformly covered with small and dispersed Fe nanoparticles. Interestingly, Fe grows from the bottom to the Ti 3+ -The inner wall and surface of TiO2-NTs, due to the rigid support of TiO2-NTs array, the nanotube structure was not destroyed, and no particles were found to aggregate and block the tubes ( Figure 1 b). Self-assembly of MIL-100(Fe) on Ti 3+ -TiO2-NTs, most of the nozzles still remain ( Figure 1 c). After calcination, Ar-Fe2O3 / Ti 3+ -TiO2-NTs maintain a cross-linked porous structure with open channels ( Figure 1 d). From the magnified image, we can see that due to the formation of spindle structure ( Figure 1 e), and finally formed a 6.926 μm thin film on the surface of the nanotubes ( Figure 1 f). Therefore, the final open porous structure and well-aligned tubular structure of the thin film electrode are beneficial for charge transfer at the electrode / electrolyte interface.

[0074] Figure 2 The visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode (Ar-Fe2O3 / Ti 3+ -TiO2-NTs), pure TiO2 nanotube photoelectrode (TiO2-NTs) prepared in Comparative Example 1, oxygen-deficient TiO2 nanotube photoelectrode (TiO2-NTs) prepared in Comparative Example 23+ -TiO2-NTs), TiO2-NTs with Fe deposited in Comparative Example 3 3+ -TiO2-NTs nanotube photoelectrode (Fe-Ti 3+ -TiO2-NTs), MIL-100(Fe) self-assembled Ti prepared in Comparative Example 4 3+ -TiO2-NTs nanotube photoelectrode (MIL-100(Fe) / Ti 3+ -TiO2-NTs) X-ray diffraction patterns. A peak at 25.3° can be observed in all thin film electrodes, confirming the successful synthesis of anatase (101) face of TiO2-NTs (JCPDS card 21-1272). 3+ -TiO2-NTs electrode retains the typical crystal peaks of TiO2-NTs. After electrodeposition, a peak at 35.63° can be easily observed, indicating that Fe 3+ -TiO2-NTs electrode was successfully deposited (JCPDS card 39-1346). MIL-100(Fe) / Ti 3+ -The XRD pattern of TiO2-NTs electrode showed unique peaks (such as 2θ=11°, 37.8°, 48.1°), which was attributed to the Ti 3 + -TiO2-NTs and MIL-100(Fe). The characteristic peaks of MIL-100(Fe) were lost after the engraving reduction process in argon atmosphere. At the same time, the intensity of the crystal peak at 35.63° increased significantly, proving that the Fe2O3 magnetic phase was successfully evolved from the crystallized MIL-100(Fe). Finally, Ar-Fe2O3 / Ti 3+ -XRD spectrum of TiO2-NTs thin film electrode confirmed the successful deposition of Fe and its self-assembly into MIL-100(Fe) and Ti 3+ -TiO2-NTs composite.

[0075] Figure 3 The visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode (Ar-Fe2O3 / Ti 3+ -TiO2-NTs) the pure TiO2 nanotube electrode (TiO2-NTs) prepared in Comparative Example 1, the oxygen-deficient TiO2 nanotube electrode (TiO2-NTs) prepared in Comparative Example 2 3+ -TiO2-NTs), TiO2-NTs with Fe deposited in Comparative Example 3 3+ -TiO2-NTs nanotube photoelectrode (Fe-Ti 3+ -TiO2-NTs), MIL-100(Fe) self-assembled Ti prepared in Comparative Example 4 3+-TiO2-NTs nanotube photoelectrode (MIL-100(Fe) / Ti 3+ -TiO2-NTs) X-ray photoelectron spectrum. Compared with TiO2-NTs, Ti 3+ -Typical Ti in TiO2-NTs 4+ The peak pair shows a slight negative shift ( Figure 3 b). Meanwhile, at 456.90eV (Ti 3+ 2p3 / 2) and 463.30eV(Ti 3+ 2p1 / 2), which is related to the change of bonding environment during the reduction process, indicating that Ti 4 + and Ti 3+ are present in the target electrode. 3+ In the spectrum fitting results of -TiO2-NTs, four binding energy peaks can be observed at 728.8, 724.9, 714.6 and 711.6 eV, corresponding to Fe 3+ 2p1 / 2, Fe 2+ 2p1 / 2,Fe 3+ 2p3 / 2 and Fe 2+ 2p3 / 2, indicating that Fe 2+ and Fe 3+ It is worth noting that the peak at 719.4 eV is higher than that of Ar-Fe2O3 / Ti 3 + -TiO2-NTs peaks all show a negative shift ( Figure 3 c). For O1s peak ( Figure 3 d), MIL-100(Fe) / Ti 3+ -TiO2-NTs O1s spectrum has peaks at 530.4eV and 532.0eV, which are lattice oxygen (Ti-O / Fe-O) and chemically adsorbed oxygen (such as -OH, -CO), respectively. 3+ In addition to the negative shift of the two main peaks, a third signal peak was observed at 532.5 eV in -TiO2-NTs, indicating that electrochemical reduction resulted in oxygen vacancies. At the same time, the peak area of ​​lattice oxygen was higher than that of MIL-100(Fe) / Ti 3+ -TiO2-NT, indicating that high-temperature calcination exposes more Ti-O / Fe-O and shares lattice electrons, resulting in a larger fractional oxygen-deficient region. The results confirm the synergistic promotion between electrochemical reduction to form oxygen vacancies and calcination in an inert atmosphere.

[0076] Figure 4 The visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode (Ar-Fe2O3 / Ti3+ -TiO2-NTs), the pure TiO2 nanotube electrode (TiO2-NTs) prepared in Comparative Example 1, the oxygen-deficient TiO2 nanotube electrode (TiO2-NTs) prepared in Comparative Example 2 3+ -TiO2-NTs), TiO2-NTs with Fe deposited in Comparative Example 3 3+ -TiO2-NTs nanotube photoelectrode (Fe-Ti 3+ -TiO2-NTs), MIL-100(Fe) self-assembled Ti prepared in Comparative Example 4 3+ -TiO2-NTs nanotube photoelectrode (MIL-100(Fe) / Ti 3+ -TiO2-NTs) UV-visible diffuse reflectance spectrum. After reduction, Ti 3+ -The absorption edge of the TiO2-NTs electrode extends to the visible light region, showing significantly enhanced visible light absorption in the range of 436nm to 700nm. After Fe electrodeposition and self-assembly, MIL-100(Fe) / Ti 3+ -TiO2-NTs exhibited excellent visible light absorption ability through sensitization by MIL-100(Fe) and maintained ( Figure 4 a). The above results verify that the electrochemical reduction of MIL-100(Fe) and Ar-Fe2O3 sensitization can effectively improve the light absorption performance of TiO2-NTs. The improvement of light absorption capacity is conducive to the photoelectrode to utilize more photocarriers, generate more active free radicals, and improve the photoelectrocatalytic performance. According to the Kubelka-Munk method, Ti 3+ -The band gap of TiO2-NTs is shortened by 2.80eV from 3.08eV of TiO2-NTs, and the Ar-Fe2O3 / Ti 3 + -The final band gap of TiO2-NTs is shortened to 2.63eV ( Figure 4 b).

[0077] During the photoelectrocatalytic reaction, 1.5 mL of sample was taken and filtered at intervals (0 min, 15 min, 30 min, 45 min, 60 min, 75 min, and 90 min of catalysis). The change in peak area at different degradation times was measured by HPLC to determine the concentration of tetracycline after degradation, thereby obtaining the degradation effect of different material electrodes on tetracycline. The results are shown in Figure 2. Figure 5 shown.

[0078] Figure 5 The visible light responsive semiconductor-MOFs hybrid photoelectrocatalytic material electrode (Ar-Fe2O3 / Ti 3+-TiO2-NTs) and the pure TiO2 nanotube electrode (TiO2-NTs) prepared in Comparative Example 1, where (a) is the degradation effect and (b) is the reaction rate. 3+ The removal efficiencies of TiO2-NTs were 15.35% and 100%, respectively. The data indicate that the photoelectrocatalytic performance of the thin film electrode was significantly enhanced after electrochemical modification and MIL-100(Fe) self-assembly. Approximately 15.35% degradation was observed in the presence of the TiO2 thin film electrode, which may be attributed to the utilization of trace visible light and the oxidation of dissolved oxygen.

[0079] Example 2

[0080] A method for treating antibiotic wastewater using a visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode, specifically treating tetracycline in the wastewater through a photoelectrocatalytic reaction using the visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode as an anode, comprising the following steps:

[0081] The visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode (Ar-Fe2O3 / Ti 3+ -TiO2-NTs) as the anode, platinum sheet as the counter electrode, and Ag / AgCl electrode as the reference electrode were placed in 60 mL of tetracycline wastewater containing sodium sulfate (the concentration of sodium sulfate in the wastewater was 0.5 mol / L, the concentration of tetracycline was 20 mg / L, and the pH was 5.3). Photoelectrocatalytic reactions were carried out under different conditions to complete the treatment of tetracycline.

[0082] Condition 1: Apply visible light source and 2V voltage for 1.5h.

[0083] Condition 2: Apply visible light source for 1.5 hours.

[0084] Condition 3: Apply 2V voltage for 1.5h.

[0085] During the three catalytic processes, 1.5 mL of sample was taken and filtered at intervals (0 min, 15 min, 30 min, 45 min, 60 min, 75 min, and 90 min of catalysis). The change in peak area at different degradation times was measured by high performance liquid chromatography to determine the concentration of tetracycline after degradation, thereby obtaining the degradation effect of the visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode on tetracycline. The results are shown in FIG. Figure 6 shown.

[0086] Figure 6 The visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode (Ar-Fe2O3 / Ti 3+-TiO2-NTs) on tetracycline degradation effect under different conditions and the corresponding reaction rate diagram, where (a) is the degradation effect and (b) is the reaction rate. Figure 6 The degradation of the three processes of photoelectrocatalysis (condition 1), photocatalysis (condition 2) and electrocatalysis (condition 3) is shown. Figure 6 It can be seen from a that when tetracycline wastewater is degraded under photocatalytic, electrocatalytic, and photoelectrocatalytic conditions, the removal rates are 24.87%, 57.76%, and 100%, respectively. The synergistic factor of the visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode for light and electricity can be calculated by equation (1):

[0087]

[0088] Among them, k PEC , k PC and k EC represent the reaction rate constants of sulfamethazine degradation in the photoelectrocatalytic, photocatalytic and electrocatalytic processes, respectively, and are represented by Figure 6 b Calculation shows that the synergistic factor in the photoelectrocatalytic process is 4.20.

[0089] Example 3

[0090] A method for treating antibiotic wastewater using a visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode, specifically treating tetracycline in the wastewater through a photoelectrocatalytic reaction using the visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode as an anode, comprising the following steps:

[0091] The visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode (Ar-Fe2O3 / Ti 3+ -TiO2-NTs) as the anode, platinum sheet as the counter electrode, Ag / AgCl electrode as the reference electrode, were placed in 60 mL of tetracycline wastewater containing sodium sulfate (the concentration of sodium sulfate in the wastewater was 0.5 mol / L, the concentration of tetracycline was 20 mg / L, and the pH was 5.3), and the photoelectrocatalytic reaction was carried out at voltages of 1.5 V, 2.0 V, and 2.5 V for 1.5 h, respectively. The photoelectrocatalytic reaction was carried out under a visible light source to complete the treatment of tetracycline.

[0092] During the photoelectrocatalytic process, 1.5 mL of sample was collected and filtered at intervals (0, 15, 30, 45, 60, 75, and 90 minutes). The change in peak area at different degradation times was measured by HPLC to determine the concentration of tetracycline after degradation. This analysis revealed the degradation effect of the visible-light-responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode on tetracycline, as shown in Figure 7.

[0093] Figure 7 The visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode (Ar-Fe2O3 / Ti 3+ -TiO2-NTs) on tetracycline degradation effect and reaction rate diagram at different voltages, where (a) is the degradation effect and (b) is the reaction rate. Figure 7 a and b show that when the applied voltage increases from 0.5 V to 2.5 V, the reaction rate increases from 0.0337 min -1 Increased to 0.0780min -1 This is likely because voltage not only increases the electron transfer rate of pollutants but also enhances the formation of active free radicals on the photoelectrode surface. After 90 minutes of degradation, the TC removal efficiency of the thin film electrode reached 88.66%, 92.06%, 94.56%, 100%, and 100% at 0.5, 1.0, 1.5, 2.0, and 2.5 V, respectively. Considering that additional reactions such as oxygen evolution may occur at higher applied voltages, 2.0 V was determined to be the most suitable applied voltage.

[0094] Example 4

[0095] A method for treating antibiotic wastewater using a visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode, specifically treating tetracycline in the wastewater through a photoelectrocatalytic reaction using the visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode as an anode, comprising the following steps:

[0096] The visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode (Ar-Fe2O3 / Ti 3+ -TiO2-NTs) as the anode, a platinum sheet as the counter electrode, and an Ag / AgCl electrode as the reference electrode were placed in 60 mL of tetracycline wastewater containing sodium sulfate (the concentration of sodium sulfate in the wastewater was 0.5 mol / L and the concentration of tetracycline was 20 mg / L) with pH values ​​of 2.0, 4.0, 6.0, 8.0, and 10.0, respectively, for photoelectrocatalytic reaction for 1.5 hours. The photoelectrocatalytic reaction was carried out under visible light source at a voltage of 2.0 V to complete the treatment of tetracycline.

[0097] During the photoelectrocatalytic process, 1.5 mL of sample was collected and filtered at intervals (0, 15, 30, 45, 60, 75, and 90 minutes). The change in peak area at different degradation times was measured by HPLC to determine the concentration of tetracycline after degradation. This analysis revealed the degradation effect of the visible-light-responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode on tetracycline, as shown in Figure 8.

[0098] Figure 8Photodegradation efficiency of tetracycline by the visible-light-responsive semiconductor heterojunction hybrid photocatalytic material electrode (Ar-Fe2O3 / Ti 3+ -TiO2-NTs) in Example 4 of the present invention at different pH values. Figure 8 a shows the effect of the initial pH value ranging from 2 to 10 on the degradation of TC. The experimental data indicate that the removal efficiency of TC first increases and then decreases with the increase of the pH value. When the pH value is 6, the best reaction rate of the thin-film electrode is 0.0684 min -1 , and the degradation efficiency of TC is 100% ( Figure 8 b). Compared with low pH values, high pH values are more conducive to the degradation of TC. This is related to the property that TC is sensitive to the pH value of the solution due to its protonation state. TC molecules exist in three different forms in aqueous solutions with different pH values, including cations (pH < 3.3), zwitterions (3.3 < pH < 7.7), and anions (pH > 7.7). Under neutral or alkaline conditions, TC molecules exist as zwitterions or anion species, which are more conducive to adsorption on the surface of the photoanode and further photocatalytic degradation. When the solution is overly alkaline, the electrolyte will be consumed excessively. Due to the lack of electrolyte, the conductivity of the solution will decrease, thereby slightly reducing the reaction rate and degradation efficiency.

[0099] Example 5

[0100] A method for treating antibiotic wastewater by using a visible-light-responsive semiconductor heterojunction hybrid photocatalytic material electrode, specifically, treating tetracycline in the wastewater through a photocatalytic reaction with the visible-light-responsive semiconductor heterojunction hybrid photocatalytic material electrode as the anode, including the following steps:

[0101] Using the visible-light-responsive semiconductor heterojunction hybrid photocatalytic material electrode (Ar-Fe2O3 / Ti 3+ -TiO2-NTs) prepared in Example 1 as the anode, a platinum sheet as the counter electrode, and an Ag / AgCl electrode as the reference electrode. After deposition for 1 min, 3 min, 5 min, 7 min, and 9 min, it is placed in 60 mL of tetracycline wastewater containing sodium sulfate (the concentration of sodium sulfate in this wastewater is 0.5 mol / L, and the concentration of tetracycline is 20 mg / L), and photocatalytic reactions are carried out at distances of 2 cm, 4 cm, 6 cm, 8 cm, and 10 cm from the light source for 1.5 h. The photocatalytic reaction is carried out under a visible-light source with a voltage of 2.0 V to complete the treatment of tetracycline.

[0102] During the photoelectrocatalytic process, 1.5 mL of sample was collected and filtered at intervals (0, 15, 30, 45, 60, 75, and 90 minutes). The change in peak area at different degradation times was measured by HPLC to determine the concentration of tetracycline after degradation. This analysis revealed the degradation effect of the visible-light-responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode on tetracycline, as shown in Figure 9.

[0103] Figure 9 The visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode (Ar-Fe2O3 / Ti 3+ -TiO2-NTs) on the degradation effect of tetracycline at different deposition times and different light intensities. Figure 8 a shows the TC degradation efficiency-time curves of thin-film photoelectrodes prepared with different electrodeposition times. When the electrodeposition time is short (1 min), the degradation efficiency of the corresponding system for TC is only 42.01%. When the deposition time is further increased to 3 min, the degradation efficiency is significantly improved (94.08%). Data comparison shows that when the deposition time is short, the self-assembly of MIL-100(Fe) may not occur because less Fe is deposited, thereby affecting the degradation efficiency. 5 minutes seems to be the optimal time for electrodeposition. When the deposition time is extended to 7 min, the degradation efficiency decreases, which may be due to excessive deposition leading to agglomeration and loss of active sites. According to the experimental results ( Figure 9 b) and Table 1 (photon flux corresponding to the distance between the electrode and the light source), when the photon flux is high enough, the final degradation efficiency of TC in the photoelectrocatalytic system under different photon fluxes is similar. However, the first-order kinetic constant (k) depends on the photon flux, 318.2 mW·cm -2 The reaction rate (k = 0.0684min -1 ) is significantly better than the reaction rate at a lower photon flux (k = 0.0138 min -1 Considering factors such as experimental equipment and light source protection, we set the distance to 6 cm to control the photon flux in subsequent experiments to 318.2 mW·cm -2 .

[0104] Table 1 Photon flux corresponding to the distance between the electrode and the light source

[0105]

[0106] The above embodiments are merely preferred embodiments of the present invention, and the scope of protection of the present invention is not limited to the above embodiments. All technical solutions that fall within the scope of protection of the present invention are within the scope of protection of the present invention. It should be noted that improvements and modifications that can be made by a person skilled in the art without departing from the principles of the present invention are also considered to be within the scope of protection of the present invention.

Claims

1. A method for treating antibiotic wastewater using a visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode, characterized in that: The method uses a visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode as an anode to treat antibiotics in wastewater through a photoelectrocatalytic reaction; the visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode uses oxygen-deficient titanium dioxide nanotubes as an electrode substrate; the oxygen-deficient titanium dioxide nanotubes are loaded with a derivative of MOFs; the MOFs derivative is Ar-Fe2O3. The preparation method of the visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode comprises the following steps: S1, immersing titanium foil in an electrolyte containing sodium fluoride and sodium sulfate, and performing anodization with graphite as a counter electrode to obtain amorphous TiO2; S2, calcining the amorphous TiO2 obtained in step S1 to obtain a titanium dioxide electrode sheet; S3. The titanium dioxide electrode obtained in step S2 is used as a working electrode, a platinum electrode is used as a counter electrode, and Ag / AgCl is used as a reference electrode. The titanium dioxide electrode is reduced in a 0.1 mol / L sodium sulfate solution at an applied voltage of -1.3 V for 10 min to 20 min, reduced in a 1 mol / L ammonium sulfate solution at an applied voltage of -1.5 V for 3 s to 5 s, and deposited in a 300 g / L ferrous sulfate solution for 3 min to 10 min to obtain Fe-doped oxygen-deficient titanium dioxide nanotubes. S4. Place the titanium dioxide electrode sheet obtained in step S3 into a mixed solution of NN dimethylformamide, 1,3,5-trimethylbenzenecarboxylic acid, nitric acid, and hydrofluoric acid, and maintain it at 150°C for 20 hours to 24 hours. Take out the treated titanium dioxide electrode sheet, wash it, dry it, and treat it in argon at 450°C for 2 hours to achieve self-assembly of MOFs on the oxygen-deficient titanium dioxide nanotubes to obtain a visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode.

2. The method according to claim 1, characterized in that The oxygen-deficient titanium dioxide nanotube has oxygen vacancies; the oxygen-deficient titanium dioxide nanotube realizes Ti 3+ of self-doping.

3. The method according to claim 1, characterized in that In the step S1, before use, the titanium foil is subjected to ultrasonic treatment in acetone and ethanol for 15 to 20 minutes respectively, then placed in a chemical polishing solution of HF:HNO3:H2O=1:3:6 for ultrasonic treatment for 30 seconds, then allowed to stand for 30 seconds, and finally subjected to ultrasonic treatment in ultrapure water for 15 minutes; the concentration of sodium fluoride in the electrolyte containing sodium fluoride and sodium sulfate is 0.3wt% to 0.5wt%, and the concentration of sodium sulfate is 0.5mol / L to 1mol / L; the DC voltage of the control power supply during the anodizing process is 20V; and the anodizing time is 3h to 5h.

4. The method according to claim 1, wherein In the step S2, the heating rate during the calcination process is 5°C / min to 7°C / min; the calcination temperature is 400°C to 500°C; and the calcination time is 1 hour to 2 hours.

5. The method according to claim 1, wherein In the S4, the mixed solution of N-N-dimethylformamide, 1,3,5-trimethylamic acid, nitric acid and hydrofluoric acid contains 30 mL to 50 mL of N-N-dimethylformamide, 1.0 g to 1.5 g of 1,3,5-trimethylamic acid, 0.27 mL to 0.30 mL of nitric acid and 0.35 mL to 0.40 mL of hydrofluoric acid.

6. The method according to claim 1, wherein In S4, the washing is carried out with ethanol and ultrapure water; the drying is carried out in an oven; the drying temperature is 60° C. to 80° C., and the drying time is 15 min to 20 min.

7. The method according to any one of claims 1 to 6, characterized in that The method comprises the following steps: placing a visible light responsive semiconductor heterojunction hybrid photoelectrocatalytic material electrode as an anode, a platinum sheet as a counter electrode, and an Ag / AgCl electrode as a reference electrode in antibiotic wastewater containing an electrolyte to carry out a photoelectrocatalytic reaction, thereby completing the treatment of the antibiotic wastewater.

8. The method according to claim 7, characterized in that The photoelectrocatalytic reaction is carried out under light conditions, the voltage during the photoelectrocatalytic reaction is 1V to 3V, and the time of the photoelectrocatalytic reaction is 1.5 hours.

9. The method according to claim 8, characterized in that The antibiotic in the antibiotic wastewater containing electrolytes is tetracycline; the concentration of the antibiotic in the antibiotic wastewater containing electrolytes is 20 mg / L; the concentration of the electrolyte in the antibiotic wastewater containing electrolytes is 25 mmol / L to 100 mmol / L; the electrolyte in the antibiotic wastewater containing electrolytes is sodium sulfate; the pH value of the antibiotic wastewater containing electrolytes is 5.0 to 5.8.

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